The long-range goal of this project is to provide an understanding of the microcirculatory effects of the anesthetics and the mechanisms responsible for their action, in both the normal and the hypovolemic state. The project is designed to provide direct quantitative microcirculatory data for constant equipotent concentrations of the anesthetic in the normal animal and in the animal subjected to hemorrhagic hypotension. Important aspects of the study include: (1) the determination of equipotent anesthetic concentrations in the bat; (2) control data obtained in the awake unanesthetized animal without prior surgery and/or anesthesia; (3) quantitative microcirculatory parameters during constant levels of anesthesia; and (4) similar microcirculatory observations during constant anesthetic depth in animals subjected to hemorrhage. These data will compliment macrocirculatory observation obtained during constant equipotent anesthetic depth. In addition, the expected results will form a basis for determining the mechanism by which the anesthetics alter the microcirculatory response to hemorrhage, and thus alter the chances of survival associated with this cardiovascular insult.